Apparatus for noncutting shaping of metallic workpieces



NOV. 4, 1969 BACHMANN 3,475,947

APPARATUS FOR NONCUTTING SHAPING OF METALLIC WORKPIECES Filed Feb. 9, 196'. 9 Sheets- Sheet 1 In venlor HORST BACHMANN ATTORNEYS H. BACHMANN Nov. 4, 1969 APPARATUS FOR NONCU'ITING SHAPING OF METALLIC WORKPIECES Filed Feb. 9, 1967 9 Sheets-Sheet? In v an [or HORST BACHMANN '54" ATTORNEYS NO"a 4, 1969 BACHMANN 3,475,947

APPARATUS FOR NONCUTTING SHAPING OF METALLIC WORKPIECES Filed Feb. 9, 1967 9 Sheets-Sheet 5 Fig. 3

In venlor HORST BACHMANN ATTORNEYS Nov. 4, 1969 H. BACHMANN 3,475,947

APPARATUS FOR NONCUTTING SHAPING OF METALLIC WORKPIECES Filed Feb. 9, 1967 v 9 Sheets-Sheet 4 Fig. 4

lnven/or: HORST BACHMANN ATTORNEYS APPARATUS FOR NONCUTTI NG SHAPING OF METALLIC WORKPIECES Filed Feb. 9, 1967 9 Sheets-Sheet 5 Inventor: A HORST BACHMANN &

ATTORNEYS Nov. 4, 1969 BACHMANN 3,475,947

' APPARATUS FOR NONCUTTING SHAPING OF METALLIC WORKPIECES Filed Feb. 9, 1967 9 Sheetsw-Sheet 6 In van/0r HORST BACHMANN ATTORNEYS APPARATUS FOR noncu'r'rme SHAPING OF METALLIC WORKPIECBS Filed Feb. 9. 196'.

H. BACHMANN Nov. 4, 1969 9 Sheets-Sheet 7 lnvenlor: HORST BACHMANN I Fla... ATTORNEYS NOV. 4, 1969 I BACHMANN 3,475,947

' APPARATUS FOR NONCUTTING SHAPING 0F METALLIC WORKPIEcES Filed Feb. 9, 1$67 9 Sheets-Sheet 8 Fig. 8 71 1/ -40 IA 5 69 I 70 lnvenlar:

HORST BACHMANN ATTORNEYS United States Patent 3,475,947 APPARATUS FOR NONCUTTIN G SHAPING OF METALLIC WORKPIECES Horst Bachmann, Haan, Rhineland, Germany, assignor to Maschinenfabrik Hasenclever Aktiengesellschaft, Duesseldorf, Germany, a corporation of Germany Filed Feb. 9, 1967, Ser. No. 614,873 Claims priority, application Germany, Feb. 10, 1966, M 68,354 Int. Cl. B21d 43/04 U.S. Cl. 72-419 12 Claims ABSTRACT OF THE DISCLOSURE The apparatus comprises a plurality of electrical upsetting devices in combination with a press means and a transfer means that grips a workpiece from an upsetting device and conveys it to the press means, said transfer means including gripper jaws and a tamping rod for properly positioning each workpiece and causing it to enter the press means.

This invention relates an an apparatus for noncutting shaping of metallic workpieces, and more particularly, it relates to an apparatus which combines a plurality of electrical upsetting machines with a forging press to produce metallic workpieces of uniform high quality.

In drop-forging operations, the objective is to shape workpieces to measurements as close as possible to those of a finished product. Forging machines and forging presses have therefore been developed in recent years which operate so accurately that in many instances chip detaching is eliminated or confined to the grinding of a few fitting parts. In many instances the potential of mod ern forging machines and presses cannot, however, be fully exploited, since burn-up and scaling, particularly where intermediate heating is required, make accurate measurement of the raw volume impossible. Also, the abrading effect of these waste materials causes rapid wear of the tools.

The recently developed electrical upsetting process has provided a significant improvement in machining possibilities. Using electrical upsetting machines, intermediate products can be supplied for final machining to produce true-to-size workpieces in drop forges to the extent that rods are used for upsetting. The rod-like blanks are heated by electrical current flowing through them and are hydraulically upset in the same operation, The method is suitable for rods of round, oval, prismatic or flat cross section. Any desired lengths of blank can be upset in a single operation. In most instances, upsetting is followed by stamping in the die, but the workpiece need not be reheated and the final stamping may be accomplished in the same heat. As a result of the particular type of electrical resistance heating from within and the resulting high speed of heating, the workpiece remains substantially free of scale. Once the proper adjustment has been made, excess heating or under-heating is avoided. This eliminates burn-up or waste due to excessive or inappropriate heating. The volume of upset can be so accurately limited that in the final stamping, workpieces are obtained which are extraordinary true to size and require very little additional machining.

Although the electrical upsetting method requires relatively little time as compared with conventional methods in which the workpiece had to be heated in the furnace, it still takes longer than the final forging which usually is accomplished with a single stroke. In order to fully exploit the potential of the press for finally forging the workpieces, it was decided to utilize a plurality of elec 'ice trical upsetting machines mounted in the vicinity of the press. However, it was found that a certain distance from the forging press had to be maintained so as to insure access to all the individual upsetting machines. As a result, the workpiece which was to be finally forged in the same heat, had to travel a relatively long path to the press, and special gripping devices became necessary for bridging the great distance.

With the use of a plurality of electrical upsetting machines in combination with a single press disposed on the outlet side thereof, a problem arose due to the fact that the individual independent upsetting machines normally operated with different hydraulic pressures and voltages. Even though these deviations were not particularly great in machines of the same type and operated under constant supervision, they resulted in differences in the quality of the finished workpieces. Also, the relatively slow speed of the machine determined the working cycles; and in addition, the construction of the press made it impossible to mount more than three electrical upsetting machines in series therewith, so that the capacity of the press was not fully exploited.

It is therefore a general object of the present invention to provide an apparatus which utilizes in combination a plurality of electrical upsetting machines and a single forging press to produce metallic workpieces of a desired shape at a relatively high production rate.

Another object of my invention is to provide an apparatus which, while operating at maximum capacity, produces workpieces of absolutely identical quality. The apparatus for accomplishing these objects and solving the aforesaid problems comprises broadly a series of electrical upsetting devices disposed on a turret-like revolving frame and a transferring device which receives an upset workpiece and delivers it to a forging press. Thus, with my apparatus, according to the invention, the upset, electrically heated, semifinished workpieces stand ready at all times on the same spot and are transferred to the press along the same short path. A particular advantage in mounting the electrical upsetting device on a turret-like revolving frame is that all of the hydraulic presses can be connected to one source of pressure medium and therefore operate at absolutely identical pressure. Also, the power for all upsetting devices may be supplied from the same source so that absolutely identical current amperage and voltage will prevail in all individual devices. In addition, transfer of the workpiece and the device required therefor are simplified and can easily be synchronized with the turret-like revolving frame.

The apparatus in accordance with the invention is particularly suited for electrical upsetting devices with vertical-stroke cylinders, the rotating frame being rotated about a vertical axis.

A further advantage of the apparatus in accordance with my invention is provided by a stationary feeding installation mounted on the outer periphery of the rotatable frame. Heretofore, the use of single upsetting devices require each device to be provided with an individual feeding device. The feeding device for the apparatu in accordance with the present invention may comprise a suitable conveyor which conveyes the workpieces at the height level of a series of input hoppers located above the upsetting apparatus. The performance of a conveyor of the type hitherto used with single upsetting machines may easily be increased to a point where it can service a plurality of upsetting devices mounted on a turretlike rotating frame.

With the turretlike arrangement of the upsetting devices in my apparatus, wherein the upset workpieces are delivered always on the same spot, I provide a unique but simple device for carrying the workpieces to the press. In accordance with a further practical proposal of the invention, the transfer device may comprise an arm rotating about a vertical axis, equipped with grippers which open and close, and rotating against the action of a spring against the shaft which drives the arm. As a result, both the turretlike frame as well as the transfer device can rotate continuously and at uniform speed. However, in order to safely introduce the workpiece into the die of the press, the gripper must be stopped temporarily. To accomplish this without also temporarily stopping the entire delivery device, the gripper is made to rotate against the force of a spring against the shaft driving it. An advantageous method of stopping the arm of the delivery device when the workpiece is being transferred to the press is to provide the arm with an abutment which, when the gripper is in alignment with the die of the press, abuts against a releasable stationary counter-stop. So long as the abutments are in contact, the parts of the transfer device which are fixedly connected with the arm continue to rotate, whereby the above mentioned spring is tensioned. As soon as the counter-stop is released by a device which will be described further below, the arm continues its interrupted rotation and, so long as the tensioned spring is relaxing, it rotates faster than the drive machinery.

To prevent breakdowns which may occur if the upset workpiece does not properly slide into the die by force of gravity, a tamping lever is preferably mounted above the gripper for urging the workpiece into the die when the gripper is in alignment therewith.

In accordance with a further proposal of the invention, a simple and practical construction is obtained if the gripper comprises two jaws swiveling about vertical axes, the jaw trailing in the direction of rotation of the arm being connected to a spring which tends to hold the jaw in closed position, while the jaw leading in the direction of rotation of the arm is opened by a cam before the gripper comes into alignment with the upsetting device lo cated at the point of transfer.

To enhance safe operation of the apparatus in accordance with the invention, the tamping lever, when in normal position, may engage the jaws of the gripper by means of locking members and secure the jaws against opening movement. This connection is easy to accomplish since the tamping lever moves in a plane vertical to the plane of movement of the gripper jaws. Therefore pins or the like devices may be connected with the tamping lever and mounted so that, in the normal position, they engage in recesses provided in the gripper jaws and hold them in a closed position.

Since the tamping lever must be accurately aligned with the grippers when the workpiece is introduced into the die, it would be in the way of the transfer device during removal of the workpiece from the upsetting de vice, were it to remain always in this position. The tamping lever has therefore been made to swivel to the side when the space above the grippers is to be freely accessible. Such lateral swivelling of the tamping lever may be realized in simple manner by causing an extension of the lever to move axially and radially on a stationary guide rod mounted eccentrically in relation to the axis of rotation of the gripper-carrying arm. During one full revolution of the transfer device, the tamping lever therefore comes only twice to stand exactly above the gripper. By suitably bending the extension of the tamping lever, the second position in which it stands directly above the gripper will not coincide with the position in which it receives the upset workpieces.

In accordance with another feature of the invention, the tamping lever is secured to a vertically displaceable rod, with its lower end sliding on a stationary cam, and a spring maintaining contact between the cam and the rod. The latter spring supplies the force for the tamping movement when the cam causes the tamping lever to move downwardly.

To obtain the necessary synchronism between the electrical upsetting device and the transfer device, the drives for the arm of the transfer device and for the turretlike frame are interconnected so that, for each full revolution of the frame, the arm completes as many full revolutions as there are upsetting devices secured on the frame.

If a press is used whose die is so far offset from the leading edge of the frame that it cannot be reached by the rotating transfer device, an additional gripper lever may be provided, which pivots along a curved path between the transfer device and the die of the forging press.

The apparatus in accordance with the invention is equipped with safety devices which bring it to a standstill in case of a breakdown, and release the press for the stamping operation only when a semifinished workpiece is properly lodged in the die.

Summarizing, some more specific objects of the present invention are to provide an apparatus combining a plurality of electrical upsetting machines and a single forging press wherein: (1) the semifinished workpieces are transferred to the press along a short path; (2) the hydraulic presses of the upsetting devices are all connected to a single source of pressure and operate at absolutely identical pressures to produce workpieces with relatively precise uniformity; (3) a unique gripper is utilized for transferring each workpiece to the forging press which is safe and reliable and which actuates to grip a workpiece and introduce it into the die of the press without slowing down or stopping the rotary movement of the apparatus; (4) a tamping lever is provided to assure that the workpiece will move properly from the transfer device into the die and also a tamping device which is movable above the gripper device to avoid the transfer device during removal of the workpiece from the upsetting device.

Other objects, advantages and features of the present invention will become apparent from the following detailed description taken with the accompanying drawings, in which:

FIG. 1 is a view in side elevation of the apparatus in accordance with the invention;

FIG. 2 is a plan view of the apparatus of FIG. 1;

FIG. 3 is an enlarged fragmentary view in side elevation of a broken-away portion of the apparatus shown in FIG. 1;

FIG. 4 is a plan view of the portion of apparatus shown in FIG. 3;

FIG. 5 is a view in elevation and in section through the transfer device of my apparatus;

FIG. 6 is an enlarged view in section taken along line VI--VI of FIG. 5 with the spring 51 broken away;

FIG. 7 is an enlarged view in section taken along line VIIVII of FIG. 5;

FIG. 8 is a view in section taken along line VIII--VIII of FIG. 5; and

FIG. 9 is a plan view similar to that of FIG. 4, show ing a modified embodiment of the invention.

In FIG. 1, numeral 1 designates a press, for example a double-sided crank press. A plurality of electrical upsetting devices are mounted in turret-like arrangement in series with the press and are generally designated by numeral 2. The upsetting devices are secured in a frame 5 which rotates on a bed 3 with the aid of a driving motor 4. The motor 4 simultaneously drives the pressure oil pumps for the upsetting cylinders. The pressure oil container is designated D. The upsetting devices each consist of pairs of cylinders 6, with anvil electrodes 7 facing each of them. Underneath the anvil electrodes 7, guide electrodes 8 are provided which supply heating current for the workpiece, the portion located between the guide electrode 8 and the anvil electrode 7 being heated by said current. To enable upsetting over a greater length, the anvil electrodes are secured to shunting cylinders 9 which are slowly retracted during the upsetting operation. The workpieces are fed to the upsetting devices by hoppers 10 mounted above the latter. Numeral 11 designates the transformers which supply the current for heating the workpieces to upsetting temperature.

The feeder device for the raw workpieces is designated 12. It comprises a chain conveyor 13 with a driving motor 14. Numeral 15 designates a discharge means in the form of a tube, while 16 is an exchangeable magazine.

As illustrated in the plan view of FIG. 2, sufiicient space remains between the individual upsetting devices of a turret-like machine comprising six such devices for installing directly on the machine the cabinets 17 for housing the electrical switching devices. This greatly simplifies the lead-in of the cable as well as the control adjustment of the operational steps.

Also in FIG. 2, a lever indicated at 18 rotates about a vertical axis, withdrawing the upset workpieces at the supply point and transferring them to the die 19 of the press 1. As will be seen in FIG. 2, each upsetting device moves by almost 360 between the feed point at the end of the tube 15 and the withdrawal point where the lever 18 grips the upset workpiece. It has been found that a single electrical upsetting operation and with a press operating with a normal number of strokes, affords sufiicient time for heating and properly upsetting the workpiece.

FIG. 3 illustrates further details of the electrical upsetting apparatus installed at the point of transfer, and a modified transfer device.

A clamp 20 with resilient jaws holds the rod-like work piece, which has been introduced into the upsetting de vice by the hopper 10, in proper position until the jaws close, and ensures that the upset workpiece does not fall out.

A transferring device 22 is mounted on a pedestal 21 and rotates with the aid of a vertical shaft 23. The drive for the shaft 23 is derived from the rotating frame 5. For this purpose, the frame is equipped with a toothed rim 29, and a cog wheel 28, suitably mounted outside the frame, engages the rim 29. Secured to a shaft along with the cog wheel 28 is a chain sprocket wheel 27, a chain leading therefrom to a further chain sprocket wheel 26 and to yet another chain wheel 25 secured on the shaft 23 (FIG. 5).

As shown in FIG. 4, the transferring device 22 is disposed between the pedestals of the press 1 so that, when the device 22 is rotated, an arm 30 equipped with gripper means sweeps over the upsetting device 6, 7, which at the time is located directly in front of the press, as well as over the die 19 of the press.

The essential details of the transfer device 22 are seen in FIG. 5. The arm 30, which is provided with grippers 35, is secured to a bushing 31 rotating with the aid of bearings 32 on the vertical driven shaft 23, the rotation being limited by a coil spring 33 disposed between the bushing and a plate 34 which is fixedly connected to the shaft 23. The upper end of the coil spring 33 is secured to the arm 30, while its lower end is secured to the disk 34. With the aid of devices which will be described hereinafter, the arm 30 can be arrested while the shaft 23 continues to rotate, whereupon, after the stop provided for this purpose has been cleared, it catches up with the rotation performed by the shaft 23 in the meantime, and, after slackening of the spring 33, resumes rotation at the same speed as the shaft 23. The arm 30 is stopped when a workpiece taken from the upsetting devices is to be transferred into the die of the press out of the grippers 35.

The workpiece is deposited by a tamping lever 36 mounted above the arm, the end portion 37 of the lever pressing upon the workpiece when the tamping lever 36 moves downwardly from the position seen in FIG. 5.

The tamping lever 36 is secured to the upper end of a vertically movable rod 38 which is displaceable in a bushing 39. The bushing 39 is connected to the arm 30. The tamping lever 36 moves upwardly and downwardly with the aid of a control cam 42. The cams control curve may be formed as a circular endless track mounted on a plate 43, which is fixedly connected to the pedestal 21. A cam following roller 41 rotatable about a horizontal axle 40* mounted on the lower end of the rod 38 establishes contact between the rod 38 and the cam 42. A tension spring 44 between the rod 38 and the arm 30 constantly urges the roller 41 against the upper surface of the cam 42.

FIG. 6 shows the structural details of the gripper 35, which comprises two halves or jaws 35a and 35b, the half 35a being rotatable about a vertical shaft 45 and the half 35b about a vertical shaft 46. A spring 47 engages the gripper-half 35b and tends to maintain the jaw in the closed position shown in FIG. 6. A sprocket 48 secured to the jaw 35a engages a toothed segment 49, which rotates about a hinge pin 50. A spring 51 engaging an anchor 52 (see FIG. 5 also) on the segment 49 maintains the segment and thereby the gripper jaw 35a normally also in the closed position shown in FIG. 6.

The end of the segment 49 facing away from the sprocket 48 abuts a plunger 53 which moves axially in a bushing 54. A roller 55 is mounted on the other end of the plunger 53 and runs along a stationary cam 56 when the arm 30 is revolving. As shown in FIG. 5, the cam 56 is disposed at the upper end of a stationary axle 60 connnected to the pedestal 21. Also secured at the upper end of the rod 60, laterally offset from its center line, is an upwardly pointing guide rod 57 which passes through an aperture in an extension 58 of the tamping lever 36. Since the guide rod 57, as shown particularly in FIG. 6, is eccentric to the axis of rotation of the arm 30, and since the tamping lever 36 is rotatably mounted on the upper end of the rod 38 with the aid of a sleeve 39, the tamping lever 36 assumes, during rotation of the arm 30, positions diverging from the radial position of the arm 30. The end 37 thereby comes out of alignment with the gripper 35, so that the latter, when transferring the workpiece from the upsetting apparatus while it is still clamped at its upper end, can grip it without being hindered by the tamping lever 36.

A sliding member 61 (FIG. 5) is adjustably secured by means of bolts through arcuate slot 62 to the disk 34 which itself is secured to the shaft 23 below the sleeve 31, as shown in FIG. 7. The sliding member 61 is thus displaceable within limits in the circumferential direction. As the sliding member 61 rotates with the shaft 23, it clears a counter-catch 64, and a catch 63 connected with the arm 30 abuts against the counter-catch 64 when the gripper 35 stands above the die 19 of the press. While the shaft 23 continues to rotate, but the arm 30 stops in order to enable transfer of the workpiece to the die, as mentioned above, the sliding member 61 approaches the counter-catch 64 and comes into contact with it after traversing a predetermined circumferential path, and dislodges it against the force of a return spring 67 as it swivels about a pivot 68. This releases the catch 63, and the arm 30 catches up with the rotation which the shaft 23 has performed in the meantime, while the spring 33 relaxes.

The catch 63, which is adjustable for accurate adjustment of the point of impact on the counter-catch 64 by means of a screw bolt and lock nuts, is mounted on an arm 65 fixedly connected with the arm 30 and projects at an angle of about therefrom (see FIG. 6). The end of the spring 51 facing away from the segment 49 is secured to another arm 66 which completes the arrangement 30 and 65 to form a star-shaped structure.

Movement of the tamping lever as shown in FIG. 5 occurs only when the gripper 35 is above the die 19 of the press. During this downward movement, the gripper 35 must release the workpiece. Additional safeguards against opening movements of the gripper 35 can be obtained in connection with the movable tamper 36 by securing, also as shown in FIGS. 5 and 8, a bracket 69 to the lower end of the rod 38, latching rods 71 adjustable by means of set screws 70 being connected therewith. The rods 71 move in slides 72 and, when the tamping lever 36 is in its uppermost position, their upper ends engage in rear extensions 73 (FIG. 6) of the gripper jaws 35a and 3512 which have suitable apertures for this purpose. Locking of the gripper jaws which is derived from the shape of the cam 42 is so synchronized with the action of the cam 56 for opening and closing the gripper jaws 35a and 35b that locking releases the gripper jaws for opening and closing movements when they grip the workpiece during its removal from the upsetting device.

A modified embodiment of the invention, as illustrated in FIG. 9, may be used when, for lack of space, it is impossible to mount the transfer device 22 between the pedestals of the press 1. In this case, a rocking lever 74 pivoting about a vertical axis 79 and fixedly connected with a toggle lever 75 is mounted in back of the transfer device 22 which is basically unchanged. A reversing pressure-medium cylinder 76 is installed on the frame of the press between the toggle lever 75 and a fulcrum 77, the cylinder 76 swinging the lever 74, back and forth along a substantially quarter-circle arcuate path. The lever 74 is equipped with a gripper 78 which receives the workpiece from the transfer device 22 and passes it on to the die 19 of the press.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

I claim:

1. An apparatus for automatic noncutting shaping of metallic workpieces, comprising in combination:

a plurality of electrical upsetting devices,

frame means for supporting said devices,

press means for shaping workpieces from said devices,

and

transfer means for receiving upset workpiece and conveying it to said press means, wherein said electrical upsetting devices have upsetting cylinders with a vertical stroke and are secured to said frame means, which is rotatable about a vertical axis.

2. The apparatus as described in claim 1 including input hoppers located above the upsetting devices and stationary feeder means on the outer periphery of said rotating frame means for conveying workpieces at the level of said input hoppers.

3. The apparatus of claim 1 including a transfer device comprising a shaft, an arm fixed to said shaft, an opening and closing gripper on said arm, and a spring, said arm and said shaft being rotatable against the action of said spring.

4. The apparatus described in claim 3 including interconnected rotational drives for said arm of said transfer means and for said frame means, said drives being interconnected so that, for each full revolution of said frame means, said arm completes as many full revolutions as there are upsetting devices secured on said frame means.

5. The apparatus described in claim 3 wherein said gripper comprises two jaws rotatable about vertical axes, spring means connected to one said jaw which trails in the direction of rotation of said arm for holding it in the closed position, and cam means for opening the other said jaw leading in the direction of rotation of said arm before said gripper comes into alignment with the upsetting device which is located at the point of transfer.

6. The apparatus described in claim 5 including locking means for engaging the jaws of the gripper and securing them against opening movement when the tamping lever is in the normal position.

7. The apparatus as described in claim 3 wherein said arm comprises a catch; and a releasable stationary countercatch, said catch being positioned against said releasable stationary counter-catch when said gripper is in alignment with the die of said press.

8. The apparatus as described in claim 7 having a releasing device comprising a sliding member connected to said shaft that drives said arm and secured thereto at an offset angle, against the normal position of the arm to the shaft and against the direction of rotation.

9. The apparatus described in claim 8 including a tamping lever located above said gripper for urging a workpiece into the die of said press, with which the gripper is in alignment.

10. The apparatus described in claim 9 wherein said tamping lever is rotatable about a vertical axis.

11. The apparatus described in claim 9 including a stationary guide rod mounted eccentrically to the axis of rotation of said arm, and extension means on said tamping lever for moving axially and radially a said guide rod.

12. The apparatus described in claim 9 having a stationary cam, a vertically displaceable rod secured to said tamping lever and having a lower end slidable on said cam, and a spring for maintaining said cam in contact with the rod.

References Cited UNITED STATES PATENTS 2,049,915 8/1936 Lewis 724l9 X 3,069,010 12/1962 Wagner 72-422 3,120,770 2/1964 Hoyt 72-422 3,149,353 9/1964 Kull 72405 X 3,233,750 2/1966 Bannon ll3ll3 MILTON S. MEHR, Primary Examiner 

